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* Licensed to Elasticsearch under one or more contributor
* license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright
* ownership. Elasticsearch licenses this file to you under
* the Apache License, Version 2.0 (the "License"); you may
* not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.elasticsearch.cluster;
import com.carrotsearch.hppc.cursors.ObjectCursor;
import com.carrotsearch.hppc.cursors.ObjectObjectCursor;
import org.elasticsearch.cluster.metadata.IndexMetaData;
import org.elasticsearch.cluster.metadata.IndexGraveyard;
import org.elasticsearch.cluster.metadata.MetaData;
import org.elasticsearch.cluster.node.DiscoveryNodes;
import org.elasticsearch.common.collect.ImmutableOpenMap;
import org.elasticsearch.gateway.GatewayService;
import org.elasticsearch.index.Index;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashSet;
import java.util.List;
import java.util.Objects;
import java.util.Set;
import java.util.stream.Collectors;
/**
* An event received by the local node, signaling that the cluster state has changed.
*/
public class ClusterChangedEvent {
private final String source;
private final ClusterState previousState;
private final ClusterState state;
private final DiscoveryNodes.Delta nodesDelta;
public ClusterChangedEvent(String source, ClusterState state, ClusterState previousState) {
Objects.requireNonNull(source, "source must not be null");
Objects.requireNonNull(state, "state must not be null");
Objects.requireNonNull(previousState, "previousState must not be null");
this.source = source;
this.state = state;
this.previousState = previousState;
this.nodesDelta = state.nodes().delta(previousState.nodes());
}
/**
* The source that caused this cluster event to be raised.
*/
public String source() {
return this.source;
}
/**
* The new cluster state that caused this change event.
*/
public ClusterState state() {
return this.state;
}
/**
* The previous cluster state for this change event.
*/
public ClusterState previousState() {
return this.previousState;
}
/**
* Returns <code>true</code> iff the routing tables (for all indices) have
* changed between the previous cluster state and the current cluster state.
* Note that this is an object reference equality test, not an equals test.
*/
public boolean routingTableChanged() {
return state.routingTable() != previousState.routingTable();
}
/**
* Returns <code>true</code> iff the routing table has changed for the given index.
* Note that this is an object reference equality test, not an equals test.
*/
public boolean indexRoutingTableChanged(String index) {
Objects.requireNonNull(index, "index must not be null");
if (!state.routingTable().hasIndex(index) && !previousState.routingTable().hasIndex(index)) {
return false;
}
if (state.routingTable().hasIndex(index) && previousState.routingTable().hasIndex(index)) {
return state.routingTable().index(index) != previousState.routingTable().index(index);
}
return true;
}
/**
* Returns the indices created in this event
*/
public List<String> indicesCreated() {
if (!metaDataChanged()) {
return Collections.emptyList();
}
List<String> created = null;
for (ObjectCursor<String> cursor : state.metaData().indices().keys()) {
String index = cursor.value;
if (!previousState.metaData().hasIndex(index)) {
if (created == null) {
created = new ArrayList<>();
}
created.add(index);
}
}
return created == null ? Collections.<String>emptyList() : created;
}
/**
* Returns the indices deleted in this event
*/
public List<Index> indicesDeleted() {
if (previousState.blocks().hasGlobalBlock(GatewayService.STATE_NOT_RECOVERED_BLOCK)) {
// working off of a non-initialized previous state, so use the tombstones for index deletions
return indicesDeletedFromTombstones();
} else {
// examine the diffs in index metadata between the previous and new cluster states to get the deleted indices
return indicesDeletedFromClusterState();
}
}
/**
* Returns <code>true</code> iff the metadata for the cluster has changed between
* the previous cluster state and the new cluster state. Note that this is an object
* reference equality test, not an equals test.
*/
public boolean metaDataChanged() {
return state.metaData() != previousState.metaData();
}
/**
* Returns a set of custom meta data types when any custom metadata for the cluster has changed
* between the previous cluster state and the new cluster state. custom meta data types are
* returned iff they have been added, updated or removed between the previous and the current state
*/
public Set<String> changedCustomMetaDataSet() {
Set<String> result = new HashSet<>();
ImmutableOpenMap<String, MetaData.Custom> currentCustoms = state.metaData().customs();
ImmutableOpenMap<String, MetaData.Custom> previousCustoms = previousState.metaData().customs();
if (currentCustoms.equals(previousCustoms) == false) {
for (ObjectObjectCursor<String, MetaData.Custom> currentCustomMetaData : currentCustoms) {
// new custom md added or existing custom md changed
if (previousCustoms.containsKey(currentCustomMetaData.key) == false
|| currentCustomMetaData.value.equals(previousCustoms.get(currentCustomMetaData.key)) == false) {
result.add(currentCustomMetaData.key);
}
}
// existing custom md deleted
for (ObjectObjectCursor<String, MetaData.Custom> previousCustomMetaData : previousCustoms) {
if (currentCustoms.containsKey(previousCustomMetaData.key) == false) {
result.add(previousCustomMetaData.key);
}
}
}
return result;
}
/**
* Returns <code>true</code> iff the {@link IndexMetaData} for a given index
* has changed between the previous cluster state and the new cluster state.
* Note that this is an object reference equality test, not an equals test.
*/
public static boolean indexMetaDataChanged(IndexMetaData metaData1, IndexMetaData metaData2) {
assert metaData1 != null && metaData2 != null;
// no need to check on version, since disco modules will make sure to use the
// same instance if its a version match
return metaData1 != metaData2;
}
/**
* Returns <code>true</code> iff the cluster level blocks have changed between cluster states.
* Note that this is an object reference equality test, not an equals test.
*/
public boolean blocksChanged() {
return state.blocks() != previousState.blocks();
}
/**
* Returns <code>true</code> iff the local node is the mater node of the cluster.
*/
public boolean localNodeMaster() {
return state.nodes().isLocalNodeElectedMaster();
}
/**
* Returns the {@link org.elasticsearch.cluster.node.DiscoveryNodes.Delta} between
* the previous cluster state and the new cluster state.
*/
public DiscoveryNodes.Delta nodesDelta() {
return this.nodesDelta;
}
/**
* Returns <code>true</code> iff nodes have been removed from the cluster since the last cluster state.
*/
public boolean nodesRemoved() {
return nodesDelta.removed();
}
/**
* Returns <code>true</code> iff nodes have been added from the cluster since the last cluster state.
*/
public boolean nodesAdded() {
return nodesDelta.added();
}
/**
* Returns <code>true</code> iff nodes have been changed (added or removed) from the cluster since the last cluster state.
*/
public boolean nodesChanged() {
return nodesRemoved() || nodesAdded();
}
/**
* Determines whether or not the current cluster state represents an entirely
* new cluster, either when a node joins a cluster for the first time or when
* the node receives a cluster state update from a brand new cluster (different
* UUID from the previous cluster), which will happen when a master node is
* elected that has never been part of the cluster before.
*/
public boolean isNewCluster() {
final String prevClusterUUID = previousState.metaData().clusterUUID();
final String currClusterUUID = state.metaData().clusterUUID();
return prevClusterUUID.equals(currClusterUUID) == false;
}
// Get the deleted indices by comparing the index metadatas in the previous and new cluster states.
// If an index exists in the previous cluster state, but not in the new cluster state, it must have been deleted.
private List<Index> indicesDeletedFromClusterState() {
// If the new cluster state has a new cluster UUID, the likely scenario is that a node was elected
// master that has had its data directory wiped out, in which case we don't want to delete the indices and lose data;
// rather we want to import them as dangling indices instead. So we check here if the cluster UUID differs from the previous
// cluster UUID, in which case, we don't want to delete indices that the master erroneously believes shouldn't exist.
// See test DiscoveryWithServiceDisruptionsIT.testIndicesDeleted()
// See discussion on https://github.com/elastic/elasticsearch/pull/9952 and
// https://github.com/elastic/elasticsearch/issues/11665
if (metaDataChanged() == false || isNewCluster()) {
return Collections.emptyList();
}
List<Index> deleted = null;
for (ObjectCursor<IndexMetaData> cursor : previousState.metaData().indices().values()) {
IndexMetaData index = cursor.value;
IndexMetaData current = state.metaData().index(index.getIndex());
if (current == null) {
if (deleted == null) {
deleted = new ArrayList<>();
}
deleted.add(index.getIndex());
}
}
return deleted == null ? Collections.<Index>emptyList() : deleted;
}
private List<Index> indicesDeletedFromTombstones() {
// We look at the full tombstones list to see which indices need to be deleted. In the case of
// a valid previous cluster state, indicesDeletedFromClusterState() will be used to get the deleted
// list, so a diff doesn't make sense here. When a node (re)joins the cluster, its possible for it
// to re-process the same deletes or process deletes about indices it never knew about. This is not
// an issue because there are safeguards in place in the delete store operation in case the index
// folder doesn't exist on the file system.
List<IndexGraveyard.Tombstone> tombstones = state.metaData().indexGraveyard().getTombstones();
return tombstones.stream().map(IndexGraveyard.Tombstone::getIndex).collect(Collectors.toList());
}
}